Spoon-shaped swim-fin



Feb. 6, 1962 E. DE BARBIERI ETAL 3,019,458

SPOON-SHAPED SWIM-FIN Filed Sept. 29, 1958 INVENTORS ETTORE DE BARB/ f FERNANDO GATT! BY Q WM ATTORNEYS The present invention relates to swin-fins and aims to obtain a fin, whose blade is shorter but larger than those of the conventional fins and which presents a very good gripping surface in the water and a sufficient resistance, the latter being achieved without increasing the thickness of longitudinal ribs and/or of the blade itself, therefrom resulting a lighter weight of the whole fin which is usually made in one piece of rubber or like, without metal reinforcement cuts.

To this end according to the invention, the fin blade is made in the shape of a spoon, that is, it is cambered in the longitudinal and in the transversal direction, and it may be also widened by a pair of side flaps.

These and other features of the invention will be apparent from the following specification of one preferred embodiment of the invention made with reference to the annexed drawing, in which:

FIGURES 1 and 2 show a fin according to the invention, viewed respectively from its topside and from its underside.

FIGURE 3 is a side elevation view of the fin.

FIGURE 4 is a longitudinal middle-section of the fin, and

FIGURE 5 is a transversal section of the fin blade in an enlarged scale.

With reference to the drawings, in its preferred embodiment, the fin comprises a shoe portion 1 having a heel section la and a toe section 11), which may be closed as shown, or constituted by fixed or adjustable straps, and a front extension or blade 2 which is stiifened by longitudinal ribs 3 extending parallel to the blade sides and possibly, but not necessarily, by a central longitudinal bead 5 which stiflens the central part of said blade 2. The active area of the fin may be also increased by providing side flaps 4 projecting from the said longitudinal ribs 3.

The shoe portion 1 comprises a substantially fiat base section from which the integral heel and toe sections 1a and 1b extend upwardly. The flexible fin 2 is also preferably integrally formed with the shoe portion, extending forwardly from said base section at a downward angle and having outwardly diverging curved edges which are faired into the foot portion 1 at the middle thereof. The stiffening ribs 3 extend from the top and bottom sides of the blade and are curved to follow the contour of the blade edges. Laterally of the ribs 3, the blade 2 has outwardly extending portions 4 which are reduced in thickness and these portions are concavely faired into the facing sides of the ribs 3.

As a difference from the conventional swim fins of like construction, the blade 2, instead of being substantially flat, is shaped like a spoon, being slightly cambered both in longitudinal direction (FIGURES 3 and 4) and in transversal direction (FIGURE 5).

Due to this spoon shape, the blade 2 and annexed flaps 4 of the fin may be made shorter and wider than the conventional fins of like construction and its active area may be even smaller than said conventional fins, due to the fact that the blade cannot bend substantially upwardly, that is in the direction of its convex side or fin top thus insuring an improved grip of the water.

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In this manner a good resistance of the blade to bending is ensured without increasing the thickness of the longitudinal ribs 3, which may be made even lighter than what was considered necessary uptodate.

As shown in FIGURES 1 and 2 of the drawing, the blade 2, including its side flaps, when provided, is curved even at its sides and thus the swim fin assumes a more rational shape from the hydrodynamic point of view, thus improving the propelling efiiciency of the fin.

We claim:

1. A fin for a swimmer, comprising a foot portion having a substantially fiat base section, an integral upwardly extending heel section and an integral upwardly extending toe section, an elongated, integrally formed flexible fin blade extending from the base of said foot portion at the toe section end thereof in alignment with the longitudinal axis of the foot portion but at a downward angle with respect to the plane of said base, said blade being longitudinally and transversely cambered, the curvature of the blade facing downwardly in reference to the heel and toe sections, and lateral stifieniug ribs on the top and the bottom side of the blade extending substantially parallel to the longitudinal edges of the blade, said ribs being faired into the foot portion at the middle thereof.

2. A fin according to claim 1 wherein said fin blade is laterally extended beyond said ribs, said laterally extended blade portions being reduced in thickness toward the rims thereof.

3. A fin according to claim 2 wherein the sides of said ribs facing said laterally extended blade portions are concavely faired into the same.

4. A fin according to claim 1 wherein a central stiffening rib extends on the top side of the blade in alignment with the longitudinal axis of said fin portion.

5. A fin for a swimmer, comprising a flexible foot portion having a substantially flat base section, an integral upwardly extending heel grip section and an integral upwardly extending toe grip section, an elongated integrally formed flexible fin blade extending from the base of said foot portion at the toe section end thereof in alignment with the longitudinal axis of the foot portion but at a downward angle with respect to the plane of said base, said blade having outwardly diverging curved longitudinal edges and being longitudinally and transversely cambered, the curvature of the blade facing downwardly in reference to the heel and toe sections, and curved lateral stiifening ribs in the blade extending from the top and the bottom side of the blade and substantially parallel to the longitudinal edges of the blade along the entire length thereof, said ribs being faired into the foot portion at the middle thereof.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,006 Churchill June 15, 1948 1,066,696 Baker July 8, 1913 2,159,972 Larson May 30, 1939 2,290,943 Conley July 28, 1942 2,313,979 Tuma Mar. 16, 1943 2,672,629 La Trell Mar. 23, 1954 2,729,832 Schmitz Jan. 10, 1956 2,737,668 Cressi Mar. 13, 1956 2,889,563 Lamb June 9, 1959 FOREIGN PATENTS 762,166 Great Britain Nov. 21, 1956 

